HomeMy WebLinkAbout06.a.4) Report on preliminary draft policy for Whole Effluent Toxicity (WET) Assessment and ControlCentral Contra Costa Sanitary District
March 31, 2911
TO: HONORABLE BOARD OF DIRECTORS
VIA: JAMES M. KELLY, P.E., GENERAL MANAGER la'
FROM: MARGARET P. ORR, P.E., DIRECTOR OF PLANT OPERATIONS It.
SUBJECT: COMMENT LETTER PRELIMINARY DRAFT POLICY FOR WHOLE
EFFLUENT TOXICITY (WET) ASSESSMENT AND CONTROL
ISSUE
The State Water Resources Control Board (SWRCB) issued a Preliminary Draft Policy
for Whole Effluent Toxicity (WET) Assessment and Control. As proposed, Central
Contra Costa Sanitary District (CCCSD) will incur violations, be exposed to enforcement
actions and citizen suits, and be required to expend significant resources where there is
no actual toxicity, simply as a result of changes in statistical methods used to calculate
toxicity results.
BACKGROUND
Original WET Program
In 1985, the WET program in the San Francisco Bay Region was founded on a strong
scientific platform as well as extensive dialogue with the regulated community.
Mr. Bhupinder Dhaliwal, Laboratory Superintendent, played an important role in helping
develop a scientifically based method bas on numerous dilutions of the plant effluent.
All efforts were based on peer - reviewed guidance (USEPA, 1985) that had been
published, accepted for nationwide implementation, and supported by EPA research
laboratories. Revisions to the program in 1991 further strengthened implementation,
testing, and statistical analysis (Suer, 1991; Anderson et al., 1991). For two decades,
toxicity testing has been in place and working to protect the beneficial uses in the San
Francisco Bay.
Early Findings for CCCSD
One of our success stories is CCCSD experienced measured toxicity in its effluent in
the early 1990s shortly after the San Francisco Regional Water Quality Control Board
(Region 2) implemented the toxicity monitoring and control program. After conducting a
Toxicity Identification Evaluation (TIE), organophosphate pesticides (Chlorpyrifos and
Diazinon) were identified to cause the measured toxicity. Mr. Dhaliwal met with the
manufacturer of the pesticides to explain the effect of them to their technical team. A
Toxicity Reduction Evaluation (TRE) program was initiated that involved extensive
public outreach regarding controlling potential sources of these particular pesticides and
practicing Integrated Pest Management (IPM) techniques in general. This program was
expanded to the greater San Francisco Bay Area under the "Our Water, Our World"
campaign. The measured toxicity was abated through these efforts and IPM has
become a standard within California because of Region 2 being strategic and thoughtful
in using fully peer - reviewed science to protect beneficial uses within the San Francisco
Bay. The cost to complete this historic TIE and initiate the THE was hundreds of
thousands of dollars. The expenditure of these funds was justified because it
addressed a true toxicity condition. This TI E/TRE was the start of a series of events
that lead to chlorpyrifos no longer being allowed for individual use.
Overview of Proposed Policy Change
The proposed policy would dramatically affect both how compliance testing is conducted for
effluents (one effluent dilution instead of a series of dilutions) as well as the manner in
which data are analyzed. CCCSD currently assesses the toxicity of the effluent using a
chronic toxicity test with control water and five dilutions of the Plant effluent. This
current statistical method is commonly called Welch's t -test and presumes the effluent
is not toxic until proven toxic (innocent until proven guilty).
The new policy differs from the existing one in that not only is a new statistical method
employed to assess compliance, but only a control water and a single concentration of
effluent are used in the toxicity test. The proposed statistical method, called the TST
approach, moves the burden of proof to the discharger; in an attempt to be more
protective of water quality it presumes the effluent is toxic until proven not toxic (guilty
until proven innocent). The statistics are so complicated that there is a lot of confusion
among Dischargers statewide. Many utilized a spreadsheet provided by the SWRCB
and only observed a 5 — 10% toxicity rate when the data were previously deemed not
toxic. Many dischargers failed to understand that their sample size was so low that the
full effect of the statistics was masked. A 5 -10/0 toxicity rate would be approximately
one false violation per year.
To add to the scientific analysis being done, CCCSD engaged Daniel Gallagher, PhD,
PE a Professor at Virginia Polytechnic Institute & State University to provide the
SWRCB a peer review and evaluation of the TST method using 1000 sample points.
Dr. Gallagher's work found the probability of improperly classifying an effluent as toxic
using the new statistical method will occur 5 -58% of the time. This means that the
Plant effluent will be deemed toxic 5 -58% of the time even though the Plant effluent is
not causing toxicity in the environment.
IMPLICATIONS
A review of CCCSD's data for the past three years indicates that three NPDES
violations would have occurred due to the change in statistics. Calculating toxicity
without looking at the curve generated from five dilutions is troublesome for a number of
0)
reasons. For regulators, false positive determinations divert enforcement resources
away from "real" water quality violations. False positive toxicity determinations in
receiving waters lead to inappropriate impairment listing that ultimately consume
regulatory resources through the development of unnecessary total maximum daily
loads (TMDLs). For CCCSD, false positive toxicity determinations can represent
effluent violations that are subject to enforcement action and citizen lawsuits. Falsely
classifying plant effluent as toxic could impact citizen acceptance of recycled water.
CCCSD may also be put in the untenable position of being required to solve a problem
that does not exist or attempt to unsuccessfully indentify sources of toxicity in response
to results that are calculated variability instead of a real toxicity issue. As indicated
above, TIEITRE work is very costly. The label of toxic will undermine public perception
of ongoing toxicity and water quality issues.
In 2004, the Court of Appeals for the District of Columbia Circuit upheld EPA's WET
test methods, but in doing so the Court noted that significant flexibility in implementation
was needed given the inherent uncertainty in the test methods. The District Court
specifically endorsed EPA's flexible enforcement policy regarding single test
exceedances, noting that "WET tests will be wrong some of the time..." The Court,
however, went further and noted that while, "by EPA's calculations, WET tests will be
wrong some of the time", this uncertainty was further tempered by an additional
safeguard of "designing the tests to give - permittees the benefit of the doubt, limiting
false positive rates to at most 5% (currently used statistics), while allowing false
negative rates up to 20 %."
CONCLUSION
The proposed policy does not provide sufficient safeguards to protect against the
inherent variability of the WET test methods and unfairly exposes CCCSD to Clean
Water Act violations, civil penalties, enforcement actions, and citizen suits for WET test
results that may not reflect actual toxic impacts.
Staff will meet with the SWRCB members to express our concerns. Staff is available to
answer any questions the Board may have.
cc: Kenton Alm, District counsel
3